On the Viability of Energy Harvesting Piezoelectric Devices for Supplemental Power Generation in Uninhabited Aircraft Systems

In this work, a global air vehicle finite element model employing empirically determined cyclic loads is used to assess the viability of energy harvesting piezoelectric devices for supplemental power generation in lightweight uninhabited aircraft systems (UASs) where the “Owl” all-composite ultralight UAS is used as a candidate proof-of-concept platform. The Owl was developed at the Mississippi State University Raspet Flight Research Laboratory as part of the U.S. Army Space Missile Defense Command High Performance Materials/Processes (HIPERMAP) Program. In the HIPERMAP flight test program, straintime histories were recorded at key locations throughout the wing and fuselage. These measured strains were used in the investigation of practical implementation of energy harvesting piezoelectric materials within the Owl UAS with the intent of harvesting electrical power from structural oscillations of the wings during operation. The total power generated was determined from a 80 KIAS 4G pullup maneuver, where piezoelectric patches were simulated in the span-wise direction along the inner surfaces of the upper and lower skins of both wings. The energy harvesting capability of the Owl UAS was insufficient due to the small oscillation frequency and low strain magnitudes of the wing during flight. Nevertheless, such energy harvesting devices remain promising for microscale UASs where power requirements are lower and the oscilation frequency of the wings is higher.